JP5046948B2 - Phase change material and thermal control device - Google Patents

Description

  The present invention relates to a thermal control device, and more particularly to a thermal control device that makes its temperature environment suitable by building materials used in houses, automobiles, transportation equipment, and the like.

  The temperate climate is relatively cool in winter and relatively hot in summer. In such a climate, the structure of the conventional house was relatively windy so that it was easy to spend summer. This structure has the drawback that in winter, the room temperature is warmed by the influence of outside air, so it does not warm easily even when the heater is turned on, and the room temperature cools immediately after the heater is turned off.

  In recent years, it has become possible to easily cool and heat indoors using air conditioning equipment such as air conditioners. In order to increase the efficiency of the air conditioning equipment, it is preferable that the house has a structure with good airtightness. Therefore, the structure of a recent house has good airtightness and a structure with high heat insulation. Improving the airtightness of the house has improved not only the cooling efficiency but also the heating efficiency.

  A house with high thermal insulation has a structure in which the indoor heat is not easily exhausted to the outside of the room, and the room temperature rises due to the indoor heat even when the outside air temperature is relatively low. There is a need to lower the room temperature.

  For this reason, it is desired to develop a structure that maintains the hermeticity of the house, reduces the cooling load, or exhausts the indoor heat to the outside without using the cooling.

  Similarly, in recent automobiles, the sealing performance has improved, so indoors no longer cool down in winter when parked outdoors, but conversely, in summer, the indoor temperature rises dramatically relative to the outside air. End up.

  The above-described problem can be solved by using a material that hardly emits heat at a low temperature and easily emits heat at a certain temperature or higher.

As thermal control devices for suitably controlling the temperature of devices mounted on spacecraft such as artificial satellites, Patent Documents 1 and 2 disclose Mn whose composition formula is represented by (A _1-x B _x ) MnO _3. Including perovskite oxides are disclosed. This material is an insulator material in the high temperature phase, a phase change material that exhibits metallic properties in the low temperature phase, and has a large amount of heat radiation in the high temperature phase and a small amount of heat radiation in the low temperature phase. By using materials, it is possible to solve the above-mentioned problems. Furthermore, this phase change material can change the temperature (transition temperature) that changes from the high temperature phase to the low temperature phase by changing the composition ratio, and further, the amount of heat radiation decreases rapidly below the transition temperature. have.

However, the phase change material represented by A _1-x B _x MnO ₃ disclosed in Patent Document 1 has a transition temperature of 280-300 K (about 10 to 30 ° C.). On the other hand, when used for residential building materials, it is desired to further increase the transition temperature.

It is disclosed that when the distribution amount x is increased, the transition temperature can be changed from 250K to 350K. However, when the distribution amount x is increased and the transition temperature is shifted to the high temperature side, the change in emissivity tends to be a gentle tendency, and the emissivity change width Δε (ε high temperature−ε low temperature) becomes small. Yes.
Japanese Patent Laid-Open No. 11-217562 JP 2002-120799 A

The perovskite oxide containing Mn, which is a phase change material (A _1-x B _x ) MnO ₃ , shows a rapid change in emissivity by changing the distribution ratio x and changing the composition ratio of A and B Although the temperature (Tc) has a functionality that can be arbitrarily changed, when the distribution amount x is increased, Tc shifts to the high temperature side, but the slope of the change in emissivity near Tc is It becomes gentle and Δε (ε high temperature−ε low temperature) also becomes small.

FIG. 4 is a diagram showing the temperature dependence of the emissivity when the distribution amount x of (La _1-x Sr _x ) MnO ₃ is changed. As shown in FIG. 4, Tc is 283 K, 309 K, which is close to room temperature, and emissivity change width Δε is about 0.4 when x = 0.175 and 0.2. And the biggest.

  However, when the distribution amount x is 0.2 or more, Tc can be shifted to the high temperature side, but the change of the emissivity in the vicinity of Tc becomes gentle, and Δε also becomes small.

On the other hand, when a perovskite oxide containing Mn, which is (A _1−x B _x ) MnO ₃ , is used for a housing building material or the like, Δc has a large value of about 0.4, Tc283K and 309K, higher than room temperature. A material having a large Δε is desired even when Tc is shifted to the high temperature side.

  In order to achieve the above-described object, the present invention employs the technical configuration described below.

That is, the present invention is an insulator material in the high temperature phase, a metallic property in the low temperature phase, a large amount of heat radiation in the high temperature phase, and a small amount of heat radiation in the low temperature phase. a phase change material used for the thermal control device for controlling the temperature of the object by using the phase change material, perovskite oxide containing Mn represented by _{(a 1-x B x)} Mn 1 + y O 3 A is at least one of La, Pr, Nd, Sm rare earth ions, B is at least one of Ca, Sr, Ba alkaline earth metal ions, and 0 ≦ A perovskite oxide containing Mn represented by (A _1−x B _x ) Mn _{1 + y} O ₃ is a phase change material characterized by x <1, 0 <y, and A is La, At least one of the rare earth ions Pr, Nd, Sm, B is a, Sr, at least one of alkaline earth metal ions of Ba, and, more preferably 0 ≦ x <1,0.005 ≦ y ≦ 0.1.

Furthermore, the present invention is a phase change material that is an insulator material in the high temperature phase, is metallic in the low temperature phase, has a large amount of heat radiation in the high temperature phase, and a small amount of heat radiation in the low temperature phase. has a phase change material layer containing, a thermal control device for controlling the temperature of the object by forming on the object, wherein the phase change _{material, (a 1-x B x} ) Mn 1 + y O 3 A perovskite oxide containing Mn, wherein A is at least one of rare earth ions of La, Pr, Nd, and Sm, and B is at least of alkaline earth metal ions of Ca, Sr, and Ba 1 and 0 ≦ x <1, 0 <y, and the phase change material is Mn represented by (A _1−x Bx) Mn _{1 + y} O ₃ Perovskite oxide containing A is a rare earth of La, Pr, Nd, Sm At least one of the ions, B is at least one of alkaline earth metal ions of Ca, Sr, and Ba, and 0 ≦ x <1, 0.005 ≦ y ≦ 0.1 Is more preferable.

  The thermal control device is the phase change material layer and may be formed on one surface of the object.

  The thermal control device includes the phase change material layer and a base material layer made of a base material, and the base material layer and the phase change material layer are sequentially formed on the object. good. The base material may be zirconium oxide, aluminum oxide, magnesium oxide, lanthanum oxide, tantalum oxide or silicon nitride, or strontium titanate, lead zirconate titanate, lanthanum zirconate titanate / lead titanate or aluminum. Lanthanum acid may be used. Furthermore, the base material layer comprises a first base material layer made of zirconium oxide, aluminum oxide, magnesium oxide, lanthanum oxide, tantalum oxide or silicon nitride, strontium titanate, lead zirconate titanate, zirconate titanate. A second base material layer made of lanthanum acid lead or lanthanum aluminum acid, and the first base material layer, the second base material layer, and the phase change material layer on the object. It may be formed in the order of.

  The object may be a building material.

  It may be a thermal control device that includes the phase change material and controls its own temperature. The heat control device may be a building material.

The perovskite oxide containing Mn which is (A _1−x B _x ) Mn _{1 + y} O ₃ of the present invention maintains a state where Δε has a large value of about 0.4 by increasing the distribution amount y. Thus, the transition temperature Tc can be shifted to the high temperature side.

The typical sectional view showing the composition of the present invention. The typical sectional view showing the composition of the present invention. The figure which shows the emissivity temperature dependence of the phase change substance of this invention. The figure which shows the emissivity temperature dependence of the phase change material of a prior art. Diagram showing the relationship between the _{(La 1-x} Sr x) the thickness of the MnO ₃ layer and the transmittance. _{(La 1-x} Sr x) diagram showing temperature characteristics of emissivity of MnO ₃ layer thickness 200nm and 600nm of.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Phase change material film | membrane 1 'Phase change material board 2 Base material film | membrane 3 Target object 4 Thin film (base film) which consists of organic resin
4 'Phase change film 5 Phase change material particles

The phase change material of the present invention is a perovskite oxide containing Mn represented by (A _1−x B _x ) Mn _{1 + y} O ₃ (A is at least one of rare earth ions of La, Pr, Nd, and Sm). , B is at least one of alkaline earth metal ions of Ca, Sr, Ba, and 0 ≦ x <1, 0 <y).

The perovskite oxide containing Mn represented by (A _1−x B _x ) Mn _{1 + y} O ₃ can shift Tc to the high temperature side by changing y which is the distribution amount of Mn. Even if Tc is shifted to a high temperature side by changing y which is the distribution amount of Mn and shifting the stoichiometric ratio, the change width Δε of the emissivity in the vicinity of Tc is not shifted by the stoichiometric ratio. It becomes possible to make it equal to Δε in the case of = 1.

  y is more preferably in the range of 0.005 ≦ y ≦ 0.1. If y is 0.1 or less, the heat treatment for obtaining the perovskite crystal structure can be carried out at the same heat treatment temperature as when the stoichiometric ratio is not shifted.

  On the other hand, if y is 0.005 or more, Tc can be shifted to high-temperature bubbles as compared with the case of the stoichiometric composition.

FIG. 3 shows an example of a temperature characteristic result of emissivity in the phase change material (A _1-x B _x ) Mn _{1 + y} O ₃ . Although the composition ratios of A and B are the same in both Comparative Example 1 and Example 1, Example 1 shows the temperature characteristics of emissivity with Mn being 5% excess (y = 0.05).

  From the results of FIG. 3, it can be seen that the Tc of Example 1 in which Mn is excessive is shifted to the high temperature side as compared with Comparative Example 1 in which Mn is not excessive, and radiation near Tc is further observed. It can be confirmed that the tendency of the rate change and Δε are equivalent.

  From this result, instead of changing the composition ratio of A and B, by shifting the distribution amount of Mn from the stoichiometric ratio, the tendency of emissivity change near Tc and Δε are equivalent to the stoichiometric composition. Tc can be shifted to the high temperature side while being held at the same temperature.

  This phase change material is preferably processed into a particulate shape, a fiber shape, a film shape, a plate shape, a block shape or the like and used in a heat control device.

  The thermal control apparatus of this invention is demonstrated in detail using typical sectional drawing. Hereinafter, the film-like phase change material layer is referred to as a phase change material film, and the plate-like phase change material layer is referred to as a phase change material plate.

FIG. 1 is an example in which a phase change material film 1 is formed on an object 3, and a base material film 2 and a phase change material film 1 are laminated on the object 3 in this order (FIG. 1A). ). At this time, the portion of the phase change material film 1 and the base material film 2 becomes a heat control device. The substrate material film 2 is preferably made of a substrate material having better adhesion than the adhesion between the phase change material and the object 3. When (A _1−x B _x ) Mn _{1 + y} O ₃ is used as the phase change material, depending on the material of the object 3, the base material film 2 includes zirconium oxide, aluminum oxide, magnesium oxide, lanthanum oxide. Any one of a first base material film made of tantalum oxide or silicon nitride and a second base material film made of strontium titanate, lead zirconate titanate, lanthanum zirconate titanate / lead titanate, or lanthanum aluminate One is formed, or on the object 3, a first base material film made of zirconium oxide, aluminum oxide, magnesium oxide, lanthanum oxide, tantalum oxide or silicon nitride, strontium titanate, zirconate titanate Lead acid, lanthanum zirconate titanate / lead or lanthanum aluminum acid The second base material film may be formed in this order.

  When used in a thermal control device, the material of the first base material film is preferably a material having high thermal conductivity. In this respect, zirconium oxide, aluminum oxide, magnesium oxide, lanthanum oxide, tantalum oxide or metal is more preferable.

  The second base material film made of strontium titanate, lead zirconate titanate, lanthanum zirconate titanate / lead, or lanthanum aluminate has a relatively close crystal structure and lattice constant. When the film is formed using the forming method, the film formation temperature can be lowered as compared with the case where the phase change material film is formed on the object 3 or the first base material film.

  When concrete, lightweight cellular concrete, earthenware, or the like is used as the material of the object 3, there is no problem in adhesion with the phase change material film, and therefore the phase change material film 1 can be directly formed on the object 3. (FIG. 1 (b)).

  Further, a phase change material plate 1 ′ in which phase change material particles 5 are dispersed in resin, concrete, or glass may be attached to the object 3 (FIG. 1C).

  After the phase change material is dispersed in a heat insulating material such as glass or resin, it can be made into a fibrous form. The example shown in FIG. 1C is a phase change material in which a phase change material is dispersed in an organic resin, glass or the like and processed into a fiber shape, for example, a glass wool-like shape disposed inside. It may be a plate 1 ′. In this case, the ratio (weight ratio) of the phase change material to the heat insulating material is preferably 0.5 or more, and more preferably 1 or more so that the phase change material is in contact with the external environment to some extent.

  Moreover, what formed the heat control apparatus containing a phase change substance in plate shape or block shape itself can also be used as a target object. Specifically, the heat control device itself can be used for building materials such as outer walls and roof tiles. For weight reduction, voids may be included to the extent that there is no problem in strength.

  FIG. 2 shows that a phase change material film 1 is formed on one surface of a film-like organic resin thin film (base film 4), and the base film 4 is attached to an object 3 via an adhesive film formed on the other surface. This is an example of pasting.

  Phase change material film 1 is formed on a base film 4 made of an organic resin thin film. (FIG. 2 (a)). On the base film 4, even if the phase change material film 1 is formed without the base material film 2, the adhesion between the base film 4 and the phase change material film 1 is good, so that it can be formed as a problem. .

  The phase change material 5 may be dispersed in the base film, and the phase change film 4 ′ in which the phase change material 5 is dispersed may be attached to the object 3 (FIG. 2B).

  The phase change material film can be formed on the organic resin film by applying a paste-like phase change material so that the film thickness after solidification is 250 nm and solidifying at 150 ° C. for 24 hours.

  Next, a method for manufacturing the structure shown in FIGS. 1 and 2 will be described.

  The phase change material can be produced using an oxide as a raw material, a sintering method for sintering carbonate, a sol-gel method, a PLD (Pulsed Laser Deposition) method, or the like. These methods are suitable when the phase change material is in the form of a plate or block. You may shape | mold to a required shape from the first, and may cut out from a molded object. For example, a phase change material plate having a thickness of 0.03 to 1 mm can be cut out from a sintered body of the phase change material and bonded to an object as a heat control device.

  Further, the obtained phase change material can be pulverized into particles, and the particles can be mixed with a binder or the like to form a film or plate.

  In addition, using an oxide thin film forming method such as vapor deposition, sputtering, aerosol deposition, sol-gel method, or PLD method, a phase change material film is directly formed on a substrate material film or an object. it can. These methods are suitable for forming a film.

  The base material film can be formed on the object by sputtering or CVD.

  When formed by sputtering or CVD, a film made of zirconium oxide, aluminum oxide, magnesium oxide, lanthanum oxide, tantalum oxide, or silicon nitride that serves as the first base material film in terms of adhesion or the like The film thickness is preferably 10 to 100 nm, and more preferably 20 to 50 nm.

  Strontium titanate and zirconate titanate as the second substrate material film on the object or on the first substrate material film for the purpose of lowering the film formation temperature when forming the phase change material film When a film of lead oxide, lanthanum zirconate titanate / lead or lanthanum aluminate is formed by sputtering or CVD in the same manner as the first base material film, the film thickness of the second base material film is 10 to 100 nm is preferable, and 20 to 50 nm is more preferable.

  When laminating the first base material film and the second base material film on the object, the sum of the film thicknesses of the first base material film and the second base material film is 20 to 200 nm. It is preferable that it is 40-100 nm, and it is more preferable.

  In the case where the base material can be formed into a plate shape, such as zirconium oxide, for example, it can be attached as a base material plate having a thickness of about 100 μm via an adhesive. In the present specification, a layer made of a base material formed by a base material film or a base material plate is referred to as a base material layer.

  Examples of the building material of the object include glass, concrete, lightweight cellular concrete, and pottery. Glass is used as a window glass for taking light into the room, and concrete or lightweight cellular concrete is used as a wall material. When the thickness is thin, it may be called a board. Pottery is often used for roof tiles.

When using a sintering method for the preparation of the phase change material _layer, when the _{(La 1-x Sr x)} Mn 1 + y O 3 as an example, the raw material oxide or carbonate _{(La 2 O 3, SrCO 3} , Mn 3 O ₄ ) is weighed and mixed so as to have a desired composition ratio, and calcined at 1000 to 1200 ° C. After calcination, the phase-change material calcined using a ball mill or the like is pulverized, granulated, mixed with a binder resin such as ethyl cellulose, pasted, applied onto the object or substrate material film, and then sintered. By doing so, it can be formed.

The thickness of the phase change material film is preferably 0.05 to 100 μm, and more preferably 0.1 to 30 μm. If the thickness is 0.05 μm or more, the change Δε of thermal emissivity in the vicinity of the transition point Tc does not become extremely small, and if the thickness is 0.1 μm or more, the thermal emissivity in the vicinity of Tc. The change Δε is equivalent to the change Δε in thermal emissivity when the stoichiometric ratio is not shifted. The upper limit of the thickness is not determined by the thermal radiation characteristics, but since the density of the phase change material film is as large as 6 g / cm ³ , if it is too thick, the weight of the thermal control device becomes heavy. Since the material unit price per g is high, the material cost becomes too high, which is not preferable. Therefore, the thickness is preferably 100 μm or less, and more preferably 30 μm or less.

  The concrete manufacturing method shown in FIGS. 1A and 1B will be described more specifically by taking a concrete board used for an outer wall of a building as an example.

  A paste mixed with a phase change material is applied onto a commercially available zirconium oxide plate having a thickness of 50 μm that is affixed to a concrete board so that the film thickness after sintering is 5 μm, and is sintered at 1200 ° C. This completes the thermal control device having the structure of FIG. When the weight of zirconium oxide (base material) becomes a problem, it is preferable to form a thick layer of the phase change material film and then thin the zirconium oxide base material to about 25 μm by polishing or the like and then apply it to a concrete board. .

  In the case of the above-described structure, a paste mixed with a phase change material may be applied directly on a concrete board so that the film thickness after sintering becomes 5 μm and sintered at 700 to 1500 ° C. In this case, a thermal control device having the structure shown in FIG. 1B can be obtained.

  If the firing temperature is 700 ° C. or higher, a phase change material film and a base material film described later can be formed. The upper limit of the sintering temperature is not particularly limited to 1500 ° C., and even if it is 1500 ° C. or higher, there is no problem. However, if it exceeds 1500 ° C., there is no design margin in the furnace body and heater for sintering. Therefore, it is not necessary to exceed 1500 ° C.

  When a phase change material film is formed on an object using a sintering method, if the sintering temperature is 700 ° C. or higher, a flat film is obtained regardless of the particle diameter. Absent.

  The thermal control device having the structure shown in FIG. 1C can be manufactured by attaching a phase change material plate 1 ′ in which particles 5 of phase change material are dispersed in resin, ceramics, or glass to the object 3. Further, the phase change material plate 1 ′ itself can be used as an object.

  The structure of FIG. 2 is obtained by forming a phase change material film on a base film made of an organic resin.

  Apply a paste mixed with the above-mentioned phase change substance particles on one surface of a base film made of organic resin with a film thickness of 25 μm so that the film thickness after drying is 5 μm, and dry at 150 ° C. for 24 hours. A phase change film having a phase change material film formed thereon is obtained.

  In the case of a window film to be attached to glass, the thickness of the phase change material film is preferably thinner in consideration of the transmittance and the like, and preferably has a thickness of about 2 to 10 μm. The maximum film thickness after solidification is preferably 75 μm or less, and more preferably 50 μm or less.

  If the film thickness after solidification does not exceed 75 μm, the weight of the building material will not be too heavy, and the work will not be hindered.

  In this case, it is preferable to use a paste obtained by mixing pulverized phase change material particles in an organic resin. The organic resin is not particularly limited as long as it is a paste-like material in which phase change material particles are mixed, but it is preferable to use a thermosetting resin in consideration of adhesion in an applied state.

  When the target is glass, the phase change material particle size is required to be flat on the surface of the phase change material film. Therefore, the maximum value of the particle size is larger than the film thickness of the thermosetting resin formed by solidification. Is preferably small, and the maximum value of the particle diameter is more preferably 85% or less of the film thickness, and further preferably 60% or less.

  On the other hand, since the surface of the phase change material film is not required to be flat if the object is other than glass, the particle size of the phase change material is excessively exposed from the surface of the thermosetting resin after solidification. And it is preferable that it is a particle size of the grade which is not missing from a thermosetting resin when a mechanical impact is added to the surface. In this case, the particle diameter of the phase change material is preferably 120% or less of the film thickness of the thermosetting resin after solidification, more preferably 100% or less, and even more preferably 80% or less.

  In order to attach the phase change film to the object, an adhesive film is formed on the surface of the phase change film opposite to the surface on which the phase change material film is formed, and the phase change film is attached to the object via the adhesive film. By pasting, the structure of FIG. 2A can be obtained.

  When the organic resin is required to have transparency in the visible light region of the phase change film, it is preferable to use a highly transparent resin such as a polycarbonate resin or a methacrylic resin, and an appropriate organic resin is appropriately used depending on the use of the phase change film. You can choose.

  Since a normal adhesive film can be used as the adhesive film, detailed description is omitted.

  In the description of the manufacturing method in FIG. 2 (a), it has been described that an adhesive film is formed on the surface of the base film and attached to the object. However, an adhesive film is formed on the surface of the object on which the phase change film is applied. Then, a phase change film may be attached.

  A phase change material can be mixed in an organic resin to form a phase change film with a film thickness of 25 μm, and an adhesive film can be formed on one surface and attached to an object.

  In this case, if the phase change film is formed in a roll shape and the phase change film is applied directly to the object from the roll, the phase change film can be applied with tension, so the film thickness of the phase change film Can be as thin as about 1 to 5 μm. On the other hand, when a film-like thin film is attached to an object such as wallpaper, the phase change film preferably has a thickness of 15 μm or more in order to maintain the flatness of the phase change film.

  If a phase change film is stuck on a target object, it is preferable that it is a film thickness of about 15-100 micrometers. If the plate has a thickness of about 1 mm, it can have the same structure as that in which the phase change material plate in which the particles of the phase change material are dispersed is bonded to the object as in FIG. It can also be the object itself.

  When forming the paste, the ratio of the binder resin and the phase change material, or the ratio of the organic resin (thermosetting resin) is not particularly limited, and the film thickness is set to a desired thickness after sintering or solidification. However, it may be prepared so as to be uniform by coating. When solidifying after application to an organic resin film, if the ratio of the phase change material to the thermosetting resin is too small, the function of the phase change material cannot be fully exhibited, so 30% by weight or more is preferable, and 50% by weight or more. More preferably. The upper limit only needs to have a viscosity capable of being applied with a uniform film thickness, and can be appropriately selected depending on the film thickness to be formed and the material of the thermosetting resin to be used.

  A description will be given of how thermal control is performed in the thermal control device having the structure of FIG.

  Hereinafter, the thermal control device of the present invention will be described with reference to a specific example using a concrete board as an object.

  When the temperature of the object 3 (concrete board) rises, the temperature of the phase change material film 1 rises through the base material film 2 and the heat emissivity increases, so that heat is transferred from the phase change material film to the outside. Radiated to prevent the temperature of the object 3 from rising. On the other hand, when the temperature of the object 3 is lowered, the temperature of the phase change material film 1 is lowered, so that the thermal emissivity is lowered and the heat radiation from the surface of the phase change material film 1 is reduced to prevent the temperature of the object 3 from being lowered. Has the effect of

  When glass is used as a building material, the glass is used as a window glass. When used for a window glass, it is required to transmit light to some extent. Since the phase change material film has a low transmittance, it may not be able to transmit visible light under the same conditions as other building materials. Therefore, an example used for a window glass will be described in detail as a modification of the above-described embodiment.

The phase change material of the present invention has a Mn stoichiometric ratio of perovskite oxide containing Mn represented by (A _1-x B _x ) MnO ₃ (A _1-x B _x ) Mn _{1 + y} O ₃ is a perovskite oxide containing Mn. Since the relationship between the film thickness and the transmittance and the film thickness and Δε is substantially equivalent to the perovskite oxide containing Mn represented by (A _1−x B _x ) MnO ₃ , (La _1−x Sr _x ) Description will be made using MnO ₃ .

FIG. 5 shows the relationship between the film thickness and the transmittance in the case of the (La _1-x Sr _x ) MnO ₃ film.

  The transmittance (p) of the optical thin film can be calculated from the equation (1).

p = exp (−4πk · d / λ) (1)
In equation (1), k is the extinction coefficient, d is the thickness of the material, and λ is the wavelength of light in vacuum.

The extinction coefficient (k) of (La _1-x Sr _x ) MnO ₃ is about 0.2 to 0.3 in the wavelength range of 0.25 to 0.8 μm that is the visible light region.

FIG. 5 shows the relationship between the film thickness and transmittance of the (La _1-x Sr _x ) MnO ₃ film when the wavelength λ is 0.5 μm, and the extinction coefficient (k) is 0.2, 0,. The relationship between the transmittance and the film thickness when the values are 25 and 0.3 is shown. In the following description, the extinction coefficient (k) is 0.25.

As the phase change material of the _glazing, when using the _{(La 1-x Sr x)} MnO 3, the transmittance, preferably at least 5%, more preferably 20% or more, is 30% or more More preferably.

  If the transmittance is 5% or more, light from the outside can be taken into the room, so that the outside can be seen from the room. If the transmittance is 20% or more, the feeling of discomfort with the normally used window glass is not so much felt, and if the transmittance is 30% or more, it can be said that it is not felt at all.

  If the film thickness is 500 nm or less, a transmittance of 5% can be secured, if it is 250 nm or less, the transmittance is 20%, and if it is 200 nm or less, the transmittance of 30% can be almost secured.

  FIG. 6 is a diagram showing temperature characteristics of emissivity of phase change material films having a film thickness of 200 nm and 600 nm. When the film thickness is decreased, Tc tends to increase and Δε tends to decrease. However, it is confirmed that there is no problem at a film thickness of 200 nm, and there is no problem up to a film thickness of 100 nm. When the film thickness is less than 100 nm, particularly less than 50 nm, Δε becomes smaller and there is no difference in emissivity due to temperature.

  As a result, the film thickness is preferably 50 to 500 nm, and more preferably 100 to 250 nm.

  When the sintering method is used, if the sintering temperature is 700 ° C. or lower, the phase change material is not sufficiently sintered, so that the softening point is 700 ° C. or higher for the glass plate serving as the base of the window glass. A glass plate is preferable, and a glass plate made of borosilicate glass or quartz glass is preferably used.

  The function of the window glass having the structure shown in FIGS. 1A and 1B will be described. The difference between FIG. 1 (b) and FIG. 1 (a) is that the base material film is formed between the glass plate and the phase change material film. Since it is sufficiently thin as compared with the plate, the same operation as that of the glass having the structure of FIG.

  When the temperature of the phase change material film 1 is higher than the transition temperature Tc, the emissivity of the phase change material film 1 is high and the amount of thermal radiation of the window glass increases.

  On the other hand, when the temperature of the phase change material film 1 is lower than the transition temperature Tc, the emissivity of the phase change material film 1 decreases and the thermal radiation amount of the window glass decreases.

As a result, when the window glass of the structure of FIG. 1 is used as a window glass of a house,
1. The temperature of the closed window can be reduced in the Hokkaido / Tohoku region or in high-cold areas where the temperature of the outside air is relatively low in summer and the indoor temperature becomes higher than the outside air if the window is closed. Therefore, it is not necessary to perform the air conditioning.
In the case of 2.1, since heat inflow from the outdoor to the indoor is promoted, the cooling efficiency cannot always be improved.

  Furthermore, if Low-E glass is used for the window glass of an automobile and the phase change material film of the present invention is formed on the glass, the temperature inside the automobile will rise above the outside air even if the vehicle is parked under the hot weather in summer. Can alleviate this.

  The window glass which uses the glass plate which consists of borosilicate glass of the structure of Fig.1 (a) as a target object can be manufactured with the following method.

When using as inclusive perovskite oxide _{Mn (La 1-x Sr x} ) Mn 1 + y O 3, the desired composition ratio of the raw material oxide or carbonate _{(La 2 O 3, SrCO 3} , Mn 2 O 3) Weigh and mix so as to be calcined at 1000 to 1200 ° C. After sintering, the phase change material calcined using a ball mill or the like is pulverized, powdered, mixed with a binder resin such as ethyl cellulose, pasted, and formed on a glass plate or substrate material film. be able to.

  When a window film in which a phase change material film is formed on a base film made of an organic resin film as shown in FIG. 2 is pasted on a glass plate, the base film is preferably a resin having high transparency and heat resistance. Resins and cyclic olefin resins are preferred.

  If the window film is made into a roll shape and the window film is directly applied from the roll onto the glass plate, the window film can be applied with tension. can do. On the other hand, when a film-like thin film is attached to an object such as wallpaper, the base film preferably has a thickness of 15 μm or more in order to maintain the flatness of the window film.

  If the window film is pasted on the object, the film thickness is preferably about 15 to 100 μm.

  An adhesive (not shown) is preferably formed on the surface of the organic resin film that faces the surface on which the phase change material film is formed. When an organic resin film is stuck on a glass plate from a roll, an adhesive may be formed on the glass.

  The film thickness of the base film is the same even for an object other than a glass plate, such as concrete.

<Example 1>
A sample for measuring thermal emissivity was prepared by the following method. First, La ₂ O ₃ , SrCO ₃ , Mn ₃ O ₄ which are raw material oxides and carbonates so as to have a composition ratio of (La _0.78 Sr _0.12 Ca _0.10 ) Mn _{1 + 0.05} O ₃ , CaCO ₃ was weighed and mixed, baked at 1000 ° C to 1200 ° C and pulverized powder was pulverized to make a paste mixed with binder resin at 1: 1 weight, and screen printing method was used on 40 mm square zirconia substrate Then, it was coated so that the thickness after firing was 10 μm, and fired at 1000 ° C. for 120 minutes.

<Comparative Example 1>
(La _0.78 Sr _0.12 Ca _0.10 ) MnO ₃ The raw material oxide and carbonate, La ₂ O ₃ , SrCO ₃ , MnO ₂ and CaCO ₃ were weighed and mixed to obtain a composition ratio of 1000 Crush the powder baked and crushed at ℃ ~ 1200 ℃, make a paste mixed with the binder resin at a weight of 1: 1, and the thickness after firing using a screen printing method on a 40mm square zirconia substrate to 10μm Then, it was baked at 1000 ° C. for 120 minutes.

  The results of measuring the thermal emissivity in the temperature range of 170K to 380K using the samples of Comparative Example 1 and Example 1 are shown in FIG.

  As shown in FIG. 3, the Tc of Comparative Example 1 was 320K, and the Tc of Example 1 was 334K.

(La _0.78 Sr _0.12 Ca _0.10 ) Mn _{1 + 0.05} O ₃ in which the Mn ratio was shifted from the stoichiometric ratio while maintaining the main composition ratio is a change in emissivity near the transition temperature. The emissivity change width Δε between the high temperature side and the low temperature side is the Mn ratio according to the stoichiometry (La _0.78 Sr _0.12 Ca _0.10 ) MnO ₃ emissivity change width Δε. Tc could be increased without changing the value.

Claims (13)

It is an insulator material in the high-temperature phase, a metallic property in the low-temperature phase, a large amount of heat radiation in the high-temperature phase, and a small amount of heat radiation in the low-temperature phase. A phase change material used in a thermal control device for controlling temperature, wherein the phase change material is a perovskite oxide containing Mn represented by (A _1-x B _x ) Mn _{1 + y} O ₃ , wherein A is , La, Pr, Nd, Sm, at least one of rare earth ions, B is at least one of Ca, Sr, Ba alkaline earth metal ions, and 0 ≦ x <1, 0 < a phase change material characterized by being y and having a phase change temperature higher than that of a perovskite oxide containing Mn represented by (A _1-x B _x ) MnO ₃ Change substance. The perovskite oxide containing Mn represented by (A _1-x B _x ) Mn _{1 + y} O ₃ is such that A is at least one of rare earth ions of La, Pr, Nd, and Sm, B is Ca, The phase change according to claim 1, wherein the phase change is at least one of alkaline earth metal ions of Sr and Ba, and 0 ≦ x <1, 0.005 ≦ y ≦ 0.1. material. Phase change material layer comprising a phase change material that is an insulator material in the high temperature phase, a metallic property in the low temperature phase, and a large amount of heat radiation in the high temperature phase and a small amount of heat radiation in the low temperature phase. A thermal control device that controls the temperature of the object by forming on the object,
The phase change material is a perovskite oxide containing Mn represented by (A _1-x B _x ) Mn _{1 + y} O ₃ , wherein A is at least one of rare earth ions of La, Pr, Nd, and Sm , B is at least one of alkaline earth metal ions of Ca, Sr, and Ba, and 0 ≦ x <1, 0 <y. The perovskite oxide containing Mn represented by (A _1-x Bx) Mn _{1 + y} O ₃ is characterized in that A is at least one of rare earth ions of La, Pr, Nd, and Sm, and B is Ca, Sr. The thermal control device according to claim 3, wherein the thermal control device is at least one of alkaline earth metal ions of Ba and 0 ≦ x <1, 0.005 ≦ y ≦ 0.1. .   The thermal control device according to claim 3, wherein the thermal control device is the phase change material layer and is formed on one surface of the object.   The thermal control device includes the phase change material layer and a base material layer made of a base material, and is formed on the object in the order of the base material layer and the phase change material layer. The thermal control device according to claim 3 or 4, characterized by the above.   The thermal control apparatus according to claim 6, wherein the base material is zirconium oxide, aluminum oxide, magnesium oxide, lanthanum oxide, tantalum oxide, or silicon nitride.   7. The thermal control device according to claim 6, wherein the base material is strontium titanate, lead zirconate titanate, lanthanum zirconate titanate / lead, or lanthanum aluminate. A first base material layer made of zirconium oxide, aluminum oxide, magnesium oxide, lanthanum oxide, tantalum oxide or silicon nitride; and strontium titanate, lead zirconate titanate, lanthanum zirconate titanate. A second substrate material layer made of lead or lanthanum aluminate,
The thermal control apparatus according to claim 6, wherein the first base material layer, the second base material layer, and the phase change material layer are formed on the object in this order.   The thermal control device according to claim 3, wherein the object is a building material. It contains an insulator material in the high temperature phase, a metallic property in the low temperature phase, a large amount of heat radiation in the high temperature phase, and a small amount of heat radiation in the low temperature phase. A thermal control device for controlling
The phase change material is a perovskite oxide containing Mn represented by (A _1-x B _x ) Mn _{1 + y} O ₃ , wherein A is at least one of rare earth ions of La, Pr, Nd, and Sm , B is at least one of alkaline earth metal ions of Ca, Sr, and Ba, and 0 ≦ x <1, 0 <y. The perovskite oxide containing Mn represented by (A _1-x Bx) Mn _{1 + y} O ₃ is characterized in that A is at least one of rare earth ions of La, Pr, Nd, and Sm, and B is Ca, Sr. The thermal control device according to claim 11, wherein at least one of alkaline earth metal ions of Ba and 0 ≦ x <1, 0.005 ≦ y ≦ 0.1. .   The thermal control device according to claim 11 or 12, wherein the thermal control device is a building material.

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